Conrec is an algorithm for contouring surfaces (in other words, it finds the contour lines of a two-dimensional function), for more information about it see the Conrec paper.
This library only aims to make Conrec algorithm available in other (more complex) projects, and it only contains the source code downloadable from the link above.
To use the library, you can either download the jar archive in the releases section, or import the artifacts in your project via Maven Central.